diff --git a/doc/vimspector.txt b/doc/vimspector.txt
index cde3fecbe..6043fb675 100644
--- a/doc/vimspector.txt
+++ b/doc/vimspector.txt
@@ -2117,6 +2117,12 @@ Rust is supported with any gdb/lldb-based debugger. So it works fine with
 - The stuff about remote agents [42] uses '"request": custom'; see the point
   about "custom" launch above
 
+- Source Mapping (i.e., enabling 'step-into' for standard library functions)
+  can be done by adding '"sourceMap": { "from_path" : "to_path" }'.
+  '"from_path"' can be found in disassembly window by going up in the stack
+  trace; '"to_path"' is just your locally installed standard library path for
+  current toolchain.
+
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                                                                *vimspector-jai*
 Jai ~